Wire line core drilling apparatus

ABSTRACT

A wire line core drilling apparatus comprising a tubular drill stem, an annular drill bit mounted at the forward end of the drill stem and an inner core tube assembly, the latter of which is provided with at least one latch dog for being lockable against longitudinal displacement relative to the drill stem and for being connectable to a retrieving device introduced in the drill stem.

United States Patent Egneliiv et al.

[451 Oct. 31, 1972 [54] WIRE LINE CORE DRILLING APPARATUS [72]Inventors: Gunnar Kristofler Egneliiv; Sune Vilhelm Eriluson, both ofSundbyberg, Sweden [73] Assignee: Atlas Copco Aktiebolag, Nacka,

Sweden [22] Filed: April 23, 1971 [21] Appl.No.: 136,804

[30] Foreign Application Priority Data March 30, 1970 Sweden ..6007/70[52] US. Cl. ..l75/246 [51] Int. Cl. .152: 25/00 [58] Field of Search175/246, 254, 244, 236, 239

[56] References Cited UNITED STATES PATENTS 1,427,268 8/1922 Dodds..175/246 1,716,092 6/1929 Smith 175/246 2,020,599 11/1935 Barrett et a1..l75/246 X 2,906,341 9/1959 Kellner et a1. ..175/246 X 3,103,981 9/1963Harper 175/246 X 3,120,283 2/1964 Braun ..l75/246 3,441,098 4/1969Martinsen ..l75/246 3,461,981 8/1969 Casper et al ..l75/246 3,485,30812/1969 Martinsen 175/236 X Primary Examiner-David H. BrownAttorney-Bauer & Goodman [5 7] ABSTRACT A wire line core drillingapparatus comprising a tubular drill stem, an annular drill bit mountedat the forward end of the drill stem and an inner core tube assembly,the latter of which is provided with at least one latch dog for beinglockable against longitudinal displacement relative to the drill stemand for being connectable to a retrieving device introduced in the drillstem.

8 Claims, 4 Drawing Figures WIRE LINE CORE DRILLING APPARATUS Thisinvention relates to a wire line core drilling apparatus having aretrievable inner core tube assembly.

The main object of the invention is to provide a means for locking theinner core tube assembly relative to the drill stem without causing anundesirable reduction of the inner core tube diameter.

Other objects and advantages of the invention will be apparent from thefollowing detailed description and drawings in which FIG. 1a is alongitudinal section through a core drilling apparatus according to theinvention and shows the locking means of the inner core tube assembly inits transport position. FIG. lb shows the same apparatus having itsinner core tube assembly locked in its core receiving position. FIG. 2shows the forward end of the drilling apparatus shown in Figs. 1a andlb. FIG. 3 is a longitudinal section through a core drilling apparatusaccording to another embodiment of the invention being arranged in acore receiving position.

In FIGS. la, lb and 2 there is shown a wire line core drilling apparatusconsisting of a multisectional tubular drill stem 1 which is providedwith an annular drill bit 2 at its forward end. The drill stem 1 isadapted for receiving an inner core tube assembly which comprises aninner core tube 3, an intermediate piece 4 and a housing 5. Theintermediate piece 4 comprises a swivel which allows the inner core tubeto rotate relative to the housing 5. In the housing 5, one or preferablytwo identical latch dogs 6 are pivotably mounted on a stub axle 7. Oneof these latch dogs are reversed relative to the other. The latch dogs 6are pivotable between an inner core tube assembly locking position (seeFIG. lb) and a transport position (see FIG. la). In the latter positionthe latch dogs are cooperating with a retrieving device 8 by means ofwhich the inner core tube assembly is manouverable within the drill stem1.

For these purposes the latch dogs 6 are provided with two arms 9 and 10which extend backward from the stub axle 7. One of these arms 9constitutes a locking heel provided for cooperation with a firstshoulder 11 at the drill stem inner wall so as to lock the inner coretube assembly against backward displacement. The other arm 10 on eachlatch dog 6 constitutes a gripping jaw and is provided with a hook 12 atits free end, which gripping jaw is intended to cooperate with acoupling means 13 of a retrieving device 8. This coupling means 13consists of a rod having a spear at its forward end. The coupling meansis connectable to the inner core tube assembly by introduction of thespear between the gripping jaws and by being caught thereof. Moreover,the retrieving device 8 is provided with an axially shiftable releasingsleeve 14. In order to release the latch dogs 6 from the coupling device13 the releasing sleeve 14 is shifted towards the spear so as to pressapart the arms 10 of the latch dogs 6, making it possible for thecoupling means 13 to be withdrawn.

Furthermore, the latch dogs 6 are provided with forward extending arms15 which are arranged to cooperate with a second shoulder 17 on thedrill stem inner wall to lock the inner core tube assembly againstforward movement relative to the drill stem. The arms 15 are alsoarranged to be acted upon by aspring 16 for biasing the latch dogstoward an inner core tube assembly locking position.

Thus, the axial locking of the inner core tube assembly with the drillstem 1 is obtained by cooperation of the latch dogs 6 of the inner coretube and the two shoulders 11 and 17 on the drill stem inner wall. Theshoulders are constituted by annular grooves in the drill stem innerwall and do not cause any reduction of the inner core tube diameter. Asthe latch dogs 6 are reversed relative to each other they will cooperatewith the shoulders on the drill stern inner wall in diametricallyopposite points whereby a symmetric and proper locking is obtained.

The inner core tube assembly 3 is introduced in the drill stem 1 bymeans of the retrieving device 8 and is connected to the latter by meansof the latch dogs 6. When the inner core tube assembly has reached itsproper drilling and core receiving position it is released from theretrieving device by means of the releasing sleeve 14. Thereupon, thearms 9 and 10 are brought into cooperation with the shoulders 11 and 17on the drill stern by means of the spring 16. Now, the inner core tubeassembly is locked against axial movement and core drilling can beperformed.

When the inner core tube 3 is filled with a core the drilling isinterrupted. The retrieving device 8 is re-introduced in the drill stem1 and is brought into cooperation with the latch dogs 6. Hereby, thespear presses the gripping jaws of the latch dogs 6 aside so that thearms 9 and 15 are moved inward breaking their cooperation with theshoulders 11 and 17. At further downward movement of the retrievingdevice 8 the gripping jaws catch the spear. The inner core tube assemblyhas now been released from the drill stem 1 and has simultaneously beeninterconnected with the retrieving device 8 and may now be withdrawnfrom the drill stem.

The core drilling apparatus shown in FIG. 3 is provided with two latchdogs of a modified type which are identical but reversed mountedrelative to each other on a transverse stub axle 107. These latch dogs106 extend rearward from the stub axle 107 and at their free ends 110they are provided with gripping jaws 1 10, provided with hooks 112.These gripping jaws are adapted for cooperation with a coupling means113 of a retrieving device 108.

Moreover, the latch dogs 106 are provided with locking heels 120 whichare arranged to cooperate with a first shoulder 111 on the drill steminner wall to lock the inner core tube assembly against backwardmovement as the inner core tube is in its core receiving position. Thelatch dogs are also provided with forward extending arms 115 which arearranged to cooperate with a second shoulder 117 on the drill stem innerwall to lock the inner core tube assembly against forward movementrelative to drill stem. The arms 115 are also arranged to be acted uponby a spring 116 for biasing the latch dogs toward the inner core tubeassembly locking positions.

The coupling means 1 13 of the retrieving device 108 consists of atubular sleeve provided with an internal annular shoulder at its forwardend. The retrieving device 108 is arranged to be connected to the innercore tube assembly by shifting the coupling sleeve 1 l3 forward over theends of the latch dogs 106 whereby the hooks 112 seize the shoulder ofthe coupling means 113. Moreover, the retrieving device is provided withan axially shiftable releasing sleeve 114 which is arranged to beshifted forward toward the annular shoulder so as to press the grippingjaws together and release the latch dogs 106 from the coupling means 1 l3.

The retrieving device 108 can now be withdrawn from the drill stem.

The invention is not limited to the shown and described embodiments butcan be freely varied within the scope of the following claims.

What we claim is l. A wire line core drilling apparatus comprising:

a tubular drill stern having a forward facing and a backward facingshoulder on the inner wall thereof;

an annular drill bit mounted at the forward end of the drill stem;

an inner core tube assembly; and

connecting means for selectively connecting said inner core tubeassembly to a retrieving device and for selectively locking said innercore tube assembly relative to the drill stern, said connecting meansincluding at least one latch dog pivotably mounted on a transverse stubaxle, said latch dog having a first locking portion for cooperation withsaid forward facing shoulder on the drill stem inner wall for preventingbackward displacement of the inner core tube assembly relative to thedrill stem, a second locking portion for cooperation with said backwardfacing shoulder on the drill stem inner wall for preventing forwarddisplacement of the inner core tube assembly relative to the drill stem,said first and second locking portions being disposed at opposite sidesof said stub axle, and a gripping jaw for cooperation with a couplingmeans on a retrieving device, by means of which the inner core tubeassembly is manouverable within the drill stem.

2. A core drilling apparatus according to claim 1 including two latchdogs which are identical but reversed mounted relative to each other onthe stub axle, said latch dogs being arranged so as to cooperate withthe shoulders of the drill stem at diametrically opposite points.

3. A core drilling apparatus according to claim 1 wherein said at leastone latch dog is biased toward inner dogs being arranged so as tocooperate with the shoulders of the drill stem at diametrically oppositepoints.

4. A core drilling apparatus according to claim 3 including two latchdogs which are identical but reversed mounted relative to each other onthe stub axle, said latch dogs being arranged so as to cooperate withthe shoulders of the drill stem at diametrically opposite points.

5. A core drilling apparatus according to claim I wherein said at leastone latch dog has two rearwardly extending arms one of which comprisessaid first locking portion and the other of which comprises said sr ppsj 6. A core drilling apparatus according to claim 5 including two latchdogs which are identical but reversed mounted relative to each other onthe stub axle, said latch core tube assembly locking positions, thelatch 9am:essa ssstts ssskas as; t drill stem when said retrievingdevice is brought into cooperation with the gripping jaws.

7. A core drilling apparatus according to claim 1 further comprisingsaid retrieving device and wherein said retrieving device coupling meansincludes a rod having a spear-shaped forward end selectively engagablewith said gripping jaw of said at least one latch dog.

8. A core drilling apparatus according to claim 7 wherein saidretrieving device coupling means further includes an axially shiftablesleeve mounted over said rod for selectively engaging said at least onelatch dog to disengage said rod from said at least one latch dog.

* II! i l

1. A wire line core drilling apparatus comprising: a tubular drill stemhaving a forward facing and a backward facing shoulder on the inner wallthereof; an annular drill bit mounted at the forward end of the drillstem; an inner core tube assembly; and connecting means for selectivelyconnecting said inner core tube assembly to a retrieving device and forselectively locking said inner core tube assembly relative to the drillstem, said connecting means including at least one latch dog pivotablymounted on a transverse stub axle, said latch dog having a first lockingportion for cooperation with said forward facing shoulder on the drillstem inner wall for preventing backward displacement of the inner coretube assembly relative to the drill stem, a second locking portion forcooperation with said backward facing shoulder on the drill stem innerwall for preventing forward displacement of the inner core tube assemblyrelative to the drill stem, said first and second locking portions beingdisposed at opposite sides of said stub axle, and a gripping jaw forcooperation with a coupling means on a retrieving device, by means ofwhich the inner core tube assembly is manouverable within the drillstem.
 2. A core drilling apparatus according to claim 1 including twolatch dogs which are identical but reversed mounted relative to eachother on the stub axle, said latch dogs being arranged so as tocooperate with the shoulders of the drill stem at diametrically oppositepoints.
 3. A core drilling apparatus according to claim 1 wherein saidat least one latch dog is biased toward inner dogs being arranged so asto cooperate with the shoulders of the drill stem at diametricallyopposite points.
 4. A core drilling apparatus according to claim 3including two latch dogs which are identical but reversed mountedrelative to each other on the stub axle, said latch dogs being arrangedso as to cooperate with the shoulders of the drill stem at diametricallyopposite points.
 5. A core drilling apparatus according to claim 1wherein said at least one latch dog has two rearwardly extending armsone of which comprises said first locking portion and the other of whichcomprises said gripping jaw.
 6. A core drilling apparatus according toclaim 5 including two latch dogs which are identical but reversedmounted relative to each other on the stub axle, said latch core tubeassembly locking positions, the latch dog being pivoted about said stubaxle such that the inner core tube assembly is unlocked relative to thedrill stem when said retrieving device is brought into cooperation withthe gripping jaws.
 7. A core drilling apparatus according to claim 1further comprising said retrieving device and wherein said retrievingdevice coupling means includes a rod having a spear-shaped forward endselectively engagable with said gripping jaw of said at least one latchdog.
 8. A core drilling apparatus according to claim 7 wherein saidretrieving device coupling means further includes an axially shiftablesleeve mounted over said rod for selectively engaging said at least onelatch dog to disengage said rod from said at least one latch dog.